WEBSTER, N.Y. - A Greece woman has been charged with buying two of the three weapons that William Spengler, Jr. used in the Christmas Eve shooting of four volunteer firefighters.

Since the rampage, many have been wondering how the man who took his own life, got his hands on the weapons.

According to law enforcement officials, Dawn Nguyen, 24, was with Spengler when she bought the guns for him in 2010. Authorities say she bought Spengler a Bushmaster assault rifle and a Mossberg shotgun in Henrietta, Monroe County.

"Providing your own name by buying a firearm, instead of the true owner's name is sometimes referred to as acting as a 'straw purchaser' and that is exactly what today's complaint alleges," said William Hochul, Jr., a U.S. Attorney for the Department of Justice.

Two-and-a-half years later, the guns were among those Spengler used in his brutal ambush of first responders that killed two men, wounded three others and burned down seven houses in Webster. Another body was found in the ashes, believed to be that of Spengler's sister Cheryl.

Webster police chief Gerald Pickering said Friday's announcement is, "important for both the fire and the police side, it's starting to bring some conclusions to our investigations."

Around 1:40 p.m. Friday New York State Police, Webster Police and the federal Bureau of Alcohol, Tobacco, Firearms and Explosives descended on the Alpine Road home where Nguyen was staying.

Nguyen, who once lived next door to Spengler on Lake Road, was taken out of the home in handcuffs.

Nguyen's charges include a state count of first-degree falsifying business records, a class E felony. She is scheduled to appear in Henrietta Town Court at 5 p.m. Jan. 8.

Investigators say that text messages with a law enforcement officer show that she bought the guns for Spengler. Legal experts say that the messages or any other evidence revealing if Nguyen lied about who the weapons were for will be key.

Court filings show that Nguyen claims she bought the guns for personal reasons and that they were stolen.

Spengler was with Nguyen, a former Lake Road neighbor, when the weapons were purchased at the Gander Mountain sporting goods store in Henrietta on June 7, 2010, Hochul said. The rambling letter Spengler left behind, which Hochul described as a "suicide note," informed authorities that the guns had come from the daughter of a neighbor.

Spengler could not legally own or purchase guns because of a felony conviction: he bludgeoned his grandmother to death in 1980.

The felony with which Nguyen is charged carries a sentence of up to 10 years in prison and a $250,000 fine.

"He was the true owner. She should have said that on the form," Hochul said.

Nguyen's lawyer, Dave Palmiere, said Friday that the guns were stolen.

"She purchased the weapons legally, and they were stolen," Palmiere said. He said Nguyen doesn't recall whether she reported the guns stolen.

Several neighbors on Alpine Road described the home as quiet, but said there was constant traffic in and out. There were five or six cars parked in the driveway Friday afternoon.

Earlier Friday, Nguyen's brother said the weapon actually was stolen from Nguyen's car.

"They think they sold him the guns, but he stole them," said Steven Nguyen, in the doorway of the family's Seneca County home.

In the doorway of a home in Greece, Nguyen's mother, Dawn Welsher said her lawyer advised her not to speak to the media. "All I can say is, I'm being set up," she said.

In a voice message recorded earlier Friday, Welsher told a Democrat and Chronicle reporter she wanted to talk.

"This is nuts," she said in the recording. "I never supplied this man with nothing. My daughter never supplied him with anything. He's setting us up."

Nguyen said his mother was questioned by police Monday. She left her home early Friday morning and went to her daughters' Greece residence, her son said.

"She said she wanted to go up there before there was an arrest," Steven Nguyen said.

Law enforcement sources had said Thursday that an arrest in the case was imminent.

Spengler shot four firefighters, killing two - Lt. Mike Chiapperini and Tomasz Kaczowka - and severely injuring two others before shooting himself fatally in the head. The fire burned for hours unchecked because of the danger Spengler posed. It destroyed seven houses and seriously damaged two others.

Welsher and her son said they are former neighbors of Spengler. They lived at 193 Lake Road, which is one house east of Spengler's address, for about five years. The family moved to Seneca County last year, the son said.

Steven Nguyen claimed that at least one gun that belonged to his sister, Dawn Nguyen, was stolen from the trunk of her car as it was parked at the family's Lake Road home.

"I think there was only one gun," said Steven Nguyen, who added that he did not know if his sister reported the theft to law enforcement.

He said Spengler was "nice, but he was a little crazy."

"He always had holes in his jeans. He used to come over every day to talk to my mom," said Steven Nguyen, the youngest of Welsher's seven children.